Full Reading Test

IELTS Academic Reading Full Test

Read the three passages and answer questions 1-40. You should spend about 20 minutes on each passage.

Turning Sunlight into Hydrogen: How Photoelectrochemical Water-Splitting Devices Work

A. Hydrogen is often presented as a “clean” fuel because it releases only water when used in a fuel cell. However, the climate benefit depends on how the hydrogen is made. Today, most industrial hydrogen comes from steam methane reforming, a process that uses natural gas and produces carbon dioxide. An alternative is to split water using sunlight, producing hydrogen without direct fossil-fuel emissions. Among the proposed routes, photoelectrochemical (PEC) water splitting attracts attention because it aims to combine light capture and electrolysis in one device. Supporters claim that PEC systems could eventually be simpler than pairing solar panels with a conventional electrolyser, although critics argue that stability and cost remain major obstacles.

B. A PEC cell typically contains two electrodes immersed in an electrolyte and separated by an ion-conducting membrane. The light-absorbing electrode is usually a semiconductor photoelectrode. When photons are absorbed, the semiconductor generates electron–hole pairs. In an n-type photoanode design, the holes move toward the electrode surface and drive the oxygen evolution reaction (OER), forming oxygen gas and releasing protons (H+) into the electrolyte. The electrons travel through an external circuit to a metal cathode (or a p-type photocathode), where they reduce protons to hydrogen gas in the hydrogen evolution reaction (HER). The membrane (often described as a proton-exchange membrane, PEM) allows ions to pass to maintain charge balance, while limiting the mixing of hydrogen and oxygen. In many lab prototypes, the electrolyte is an acidic solution; in others it is alkaline, which changes which ions move most readily (H+ in acid, OH− in base).

C. The sequence of events in a working PEC device can be described as a chain of conversions. First, light absorption depends on the semiconductor’s band gap: if the band gap is too large, much of the solar spectrum is not harvested; if it is too small, the voltage generated may be insufficient to drive the reactions. Second, photogenerated charges must be separated before they recombine. Recombination, which converts useful charges back into heat, can occur in the bulk of the material or at its surface. Third, charges must transfer into the electrolyte at catalytic sites. For the photoanode, a thin catalyst layer (for example, iridium oxide in acidic cells or nickel–iron oxyhydroxide in alkaline cells) can lower the overpotential for OER. Finally, products must be removed: hydrogen bubbles at the cathode and oxygen bubbles at the anode. Researchers note that bubble coverage can block light and reduce active area, so cell geometry and flow conditions are not minor engineering details but part of performance.

D. Different research groups have pursued different material strategies. Professor Akira Fujishima’s early work in Japan helped popularise titanium dioxide photoanodes, valued for chemical stability but limited by a large band gap that absorbs mainly ultraviolet light. In Germany, several research groups have reported tandem designs that stack two absorbers to capture more of the spectrum and increase photovoltage, for example a wide-band-gap top layer above a narrow-band-gap bottom layer. In the United States, researchers at a national laboratory have emphasised protective coatings—such as thin, transparent metal oxides—that allow charge transfer while shielding sensitive semiconductors from corrosion. Meanwhile, teams in South Korea have explored earth-abundant catalysts to reduce reliance on scarce metals like iridium. These approaches illustrate a trade-off: the most efficient materials are not always the most durable, and the most durable are not always the cheapest.

E. Evaluating a PEC device requires more than reporting that “hydrogen was produced.” A common metric is the solar-to-hydrogen (STH) efficiency, defined as the chemical energy of the hydrogen output divided by the solar energy input. In simplified reporting, some studies assume standard sunlight of 1000 W per square metre (often called one sun) and use the higher heating value (HHV) of hydrogen. Stability is frequently measured as the time a device operates before its current drops by a specified percentage, such as 10%. Importantly, high STH measured for minutes does not guarantee a practical system. A device might show 12% STH for one hour but degrade quickly, while another might show 6% STH for 1000 hours. Some authors argue that long-lived moderate performance is more valuable than short-lived record performance, because replacement and downtime increase the cost per kilogram of hydrogen.

F. Scaling PEC technology also raises safety and systems questions. Hydrogen and oxygen form an explosive mixture over a wide range of concentrations, so preventing gas crossover is essential. The membrane helps, but imperfections, pressure differences, or mechanical stress can increase mixing. For this reason, some demonstrators operate with the hydrogen side at slightly higher pressure to discourage oxygen migration, while others incorporate recombination catalysts in vent lines as a safeguard. Water management matters too: in outdoor devices, evaporation can concentrate salts and change pH, which can reduce conductivity and accelerate corrosion. Proponents of PEC point out that, in principle, panels could be deployed near where hydrogen is needed, reducing transport. Opponents reply that distributed hydrogen production complicates monitoring and maintenance. These are not purely technical disagreements; they reflect different assumptions about how energy infrastructure should evolve.

G. Despite the challenges, PEC research continues because its goals align with broader decarbonisation strategies. Several roadmaps propose that a commercially attractive device would need to combine a double-digit STH efficiency with multi-year stability and low-cost materials. Achieving all three simultaneously is difficult. Yet incremental progress is clear: improved catalysts reduce overpotential, protective layers slow corrosion, and tandem absorbers raise voltage. If future prototypes can demonstrate reliable operation in real sunlight—through seasonal temperature swings and imperfect water quality—PEC may become one of several complementary routes to low-carbon hydrogen. Whether it becomes dominant will depend not only on laboratory performance but also on manufacturing methods, safety regulation, and the relative cost of competing technologies such as photovoltaic-plus-electrolyser systems.

Cross-section of a photoelectrochemical (PEC) water-splitting cell

Label the diagram below. Write NO MORE THAN TWO WORDS AND/OR A NUMBER for each answer.

Comparing efficiency and stability of two hypothetical PEC devices

Mapping the Rise of Urban Heat Islands: Data, Mechanisms, and Mitigation

A. In many large cities, summer temperatures are no longer experienced as a uniform blanket of heat. Instead, they form a patchwork in which some neighbourhoods remain several degrees warmer than nearby parks or suburbs. This pattern is commonly described as the Urban Heat Island (UHI) effect: the tendency for built-up areas to record higher air and surface temperatures than surrounding rural land. Although the idea has been discussed for over a century, it has become a pressing policy issue because heatwaves are increasing in frequency and intensity in several regions. Public health agencies now treat heat as a measurable environmental risk rather than an inconvenience, and city governments increasingly ask a data-driven question: where, when, and why does the city heat up most?

B. The magnitude of a city’s heat island is typically expressed as a temperature difference between an urban location and a rural reference site. Long-term comparisons of weather-station records across large metropolitan regions in the United States suggest that, on clear and calm summer nights, the average UHI intensity for large cities often falls between 1°C and 3°C, though individual nights can exceed 5°C. Similar ranges have been reported for European cities, especially during heatwave periods. Importantly, the UHI is frequently strongest at night because urban materials release stored heat slowly, while rural areas cool faster. However, not all cities behave identically: coastal cities with persistent breezes may show smaller differences, and arid-region cities sometimes exhibit a daytime heat island but a weaker nocturnal signal.

C. Researchers now combine ground stations with satellite observations to map heat at fine spatial scales. One common satellite-derived metric is Land Surface Temperature (LST), which captures the ‘skin’ temperature of roofs, roads, and vegetation. LST is not the same as the air temperature felt by pedestrians, yet it reveals where heat is absorbed and later released. In a case study of Barcelona, a team of urban geographers compared daytime LST with neighbourhood tree cover and found that districts with dense canopy tended to show lower peak surface temperatures. A related study in Singapore highlighted that small parks can create measurable “cool islands” extending into adjacent streets, but the cooling distance depends on wind, building height, and park shape. These findings have encouraged cities to treat heat as a spatial planning variable that can be mapped, predicted, and potentially redesigned.

D. The physical mechanisms behind the heat island are relatively well understood. First, dark and impervious surfaces such as asphalt have a low albedo, meaning they absorb a high proportion of incoming solar radiation. Second, many construction materials (concrete, brick) have high heat capacity and store energy during the day, releasing it after sunset. Third, urban form reduces cooling: dense street canyons can trap longwave radiation and restrict ventilation. Fourth, cities often replace evapotranspiring vegetation with sealed surfaces, reducing evaporative cooling. Finally, anthropogenic heat—waste heat from vehicles, air conditioners, and industry—adds energy directly to the urban atmosphere. Studies in Tokyo have estimated that anthropogenic heat can be a noticeable fraction of the nocturnal heat budget in commercial districts, particularly in winter. Nevertheless, the relative importance of these mechanisms differs across cities and even across neighbourhoods, which is why local measurements matter.

E. Not all residents experience the heat island equally. Epidemiologists increasingly link UHI patterns to social vulnerability, arguing that heat risk reflects both exposure and capacity to cope. In a multi-city analysis, a team of public-health researchers reported that neighbourhoods with less tree cover and higher proportions of elderly residents tended to show higher heat-related emergency calls during extreme events. However, the authors cautioned that the relationship is not purely climatic: housing quality, access to cooling, and working conditions also matter. Some city officials claim that increasing tree cover is the single most effective intervention for reducing heat-related illness, but this assertion is contested because trees require water, time to mature, and maintenance, and their benefits can be smaller in narrow streets where airflow is limited. The debate has shifted toward targeted interventions guided by local data rather than one-size-fits-all solutions.

F. Mitigation strategies generally fall into three categories: increasing shade and evapotranspiration, raising surface reflectivity, and improving urban ventilation. Urban forestry and green roofs aim to add vegetation, while “cool roofs” and reflective pavements increase albedo. A well-documented programme in Los Angeles reported measurable reductions in surface temperatures on treated streets, though the effect on air temperature at pedestrian height was smaller and varied by time of day. Another approach is to preserve or create ventilation corridors—aligned open spaces that allow breezes to penetrate dense districts. In Stuttgart, Germany, planning regulations protect certain valley pathways for airflow, illustrating how geography can be used as a cooling asset. Most researchers agree that no single measure is sufficient; instead, combinations must be chosen based on land use, water availability, and the local climate. A practical challenge is that the same intervention may deliver different benefits in different seasons—for example, reflective surfaces can reduce summer heat but may slightly increase winter heating demand in cooler climates.

G. To allocate resources effectively, cities increasingly rely on “heat action” analytics: identifying hotspots, forecasting dangerous days, and evaluating interventions. A typical workflow begins with collecting air temperature from fixed weather stations and mobile sensors mounted on vehicles or bicycles. These measurements are then combined with satellite LST, land-cover maps, and building data to model heat at the block level. The output is often a hotspot map that highlights areas where high temperatures coincide with high vulnerability. Some municipalities now publish these maps and use them to prioritise tree planting, cool-roof subsidies, or the placement of public cooling centres. Yet there are unresolved questions about data quality and transparency. Mobile sensors can be biased by traffic conditions, and satellite snapshots may miss nighttime patterns. The emerging consensus in the research literature is that heat governance should be iterative: measure, intervene, re-measure, and revise—treating the city as a system whose thermal behaviour can be monitored over time.

Urban–Rural Temperature Profile Across a City (Day vs Night)

Urban Heat Island (UHI) intensity is usually measured as the temperature difference between an urban site and a (24) ________ reference location. Long-term station records suggest that on clear, calm summer nights, many large U.S. cities show an average UHI of (25) ________, and the effect is often strongest at night because urban materials release stored heat slowly. To map heat in detail, researchers combine ground stations with satellite-based Land Surface Temperature (LST), which measures the (26) ________ temperature of surfaces like roofs and roads. Studies also show that adding vegetation can reduce peak temperatures, but the cooling effect of parks depends on factors such as wind and (27) ________.

• rural
• urban
• 1-3°C
• over 5°C
• skin
• air
• building height
• park size
• albedo

The Politics of Remembering: How Nations Build Public Memory

• i. The growing use of eyewitness testimony in memorial museums
• ii. How the layout of an exhibition can guide visitors’ responses
• iii. Remembering as a process of institutional selection
• iv. Why compulsory history courses encourage students to debate
• v. Recurring patterns in the way schools present the national past
• vi. Theories of how groups shape memory, and the case for openness
• A. presented as a single, fixed story so that citizens share one interpretation of the past.
• B. reposted by trusted community figures such as teachers or local journalists.
• C. supported by algorithmic recommendation systems that prioritise long-form explanations.
• D. open about its sources and uncertainties, allowing revision when new evidence appears.
• E. curated through institutions that decide what to emphasise and what to leave in the background.

A. Public memory is often described as a society’s shared understanding of its past, but it is not simply a larger version of individual recollection. It is produced through institutions—schools, museums, courts, archives, and the media—that select certain events for emphasis and leave others in the background. The historian Pierre Nora argued that modern states increasingly rely on “sites of memory” (monuments, anniversaries, museums) because everyday traditions no longer transmit the past automatically. This does not mean that public memory is always invented from nothing; rather, it is curated. The same war, migration, or revolution can be narrated as a heroic founding story, a cautionary tragedy, or an unfinished moral debt depending on who is doing the narrating and for what purpose. In this sense, memory is political not because it is necessarily false, but because it is structured by choices about what counts as significant.

B. One influential approach to understanding these choices comes from Maurice Halbwachs, who claimed that remembering is guided by “social frameworks”: people recall the past using categories and language supplied by the groups they belong to. Later, Jan Assmann distinguished between communicative memory (informal, living recollections shared within families and communities) and cultural memory (formalised representations preserved across generations). Communicative memory typically spans about three or four generations; once eyewitnesses die, stories become less flexible and more dependent on records. This transition has consequences. When a state turns a contested episode into a fixed curriculum topic or a museum exhibition, it can stabilise knowledge, but it can also reduce complexity. The writer of this passage argues that the most reliable public memory is not the one that claims perfect neutrality, but the one that openly displays its sources and uncertainties, making revision possible when new evidence emerges.

C. Education is a powerful tool in this process because school systems reach most citizens while they are still forming their sense of identity. Comparative research by the Global Textbook Forum (a consortium of curriculum analysts based in Geneva) found that national history textbooks tend to follow three recurring patterns. First, “teleological” narratives present the nation as moving inevitably toward its current form, making earlier conflicts appear necessary steps. Second, “moral exemplar” narratives highlight episodes of suffering or resistance to teach civic lessons, sometimes by simplifying the motives of historical actors. Third, “pluralist” narratives present multiple perspectives, often through primary-source extracts and explicit discussion questions. The Forum’s 2019 review of textbooks in Japan, Turkey, and Canada reported that pluralist design was most common in elective senior courses rather than compulsory lower-secondary courses. The report did not claim that pluralist textbooks automatically create tolerant citizens, but it did note that they provide more opportunities for students to recognise disagreement as a normal feature of historical inquiry.

D. Museums and memorials translate the past into physical experience, and their design choices can guide visitors toward particular interpretations. Consider the difference between an object-centred gallery and an immersive narrative exhibition. The former tends to emphasise authenticity—original artefacts, dated labels, provenance—while the latter often uses soundscapes, reconstructed rooms, and guided storylines. The Memorial Design Institute in Berlin has described a common “visitor pathway” in contemporary memorial museums: an entry threshold that marks a transition from everyday space, a chronology corridor that arranges events in sequence, a testimony zone featuring recorded witnesses, an evidence archive room displaying documents and photographs, and finally a reflection chamber where visitors are invited to write comments or view a pledge wall. Although these elements can deepen understanding, critics argue that highly choreographed pathways risk turning moral reflection into a predictable ritual. Nevertheless, when museums disclose curatorial decisions—why one photograph is displayed and another omitted—they can encourage critical engagement rather than passive consumption.

E. Courts and commissions offer a different route to public memory: they establish an official record through formal procedures. Truth commissions, used in countries such as South Africa, Chile, and Sierra Leone, typically collect statements, hold hearings, and publish final reports. Legal settings impose constraints—rules of evidence, cross-examination, and definitions of responsibility—that can make some experiences easier to recognise than others. For example, interpersonal violence may be documented more readily than structural harms such as forced displacement through economic policy. Yet commissions can also broaden what counts as historical knowledge by validating testimonies that were previously dismissed. The legal scholar Ruti Teitel has described how transitional justice can give a society an official account of the past by naming perpetrators and victims, but such an account can also freeze debate if later generations treat the report as the last word. In the author’s view, commissions are most constructive when their archives remain accessible and when schools and media treat their findings as starting points for inquiry rather than sacred texts.

F. Digital media has intensified the struggle over memory by accelerating circulation and lowering the cost of publication. Online platforms allow local communities to build archives, annotate photographs, and share family documents, sometimes challenging state narratives. At the same time, algorithmic recommendation systems can prioritise emotionally charged content, rewarding simplified stories over careful contextualisation. Research by the Media Futures Lab, an independent research group, tracked the spread of historical misinformation during three national anniversaries (in Poland, India, and Brazil) and found that posts containing a single striking image with a brief caption were shared more frequently than posts linking to long-form explanations. The study also reported that corrective posts from official institutions had limited reach unless they were reposted by trusted community figures such as teachers or local journalists. This suggests that authority alone does not guarantee visibility online; credibility is increasingly relational and network-based.

G. If public memory is unavoidably selective, the central question becomes how selection is governed. Some governments attempt to legislate memory through “memory laws” that criminalise denial of certain atrocities or mandate specific terminology. Supporters claim such laws protect vulnerable groups from hate and prevent falsification; opponents argue that they risk politicising scholarship and discouraging legitimate debate. A pragmatic alternative is to focus on procedural standards: open archives, independent historical commissions, and transparent museum and curriculum review processes. The writer maintains that societies should judge public memory less by whether it feels unified and more by whether it remains contestable—capable of incorporating new documents, new voices, and revised interpretations without collapsing into cynicism. In other words, the healthiest national memories are not those that erase conflict, but those that provide citizens with tools to argue about the past responsibly.

A. Pierre Nora

B. Maurice Halbwachs

C. Jan Assmann

D. Global Textbook Forum

E. Memorial Design Institute

F. Ruti Teitel

G. Media Futures Lab

H. South Africa

4. According to Paragraph C, what is the problem if a semiconductor’s band gap is too small?

• A. Much of the solar spectrum passes through without being harvested.
• B. The voltage it generates may be too low to drive the reactions.
• C. Charges recombine at the surface before they reach the catalyst.
• D. Gas bubbles collect on the electrode and block the incoming light.

5. Why does the writer say in Paragraph C that cell geometry and flow conditions are ‘part of performance’?

• A. They decide which catalyst can be used on the photoanode.
• B. They control whether the electrolyte is acidic or alkaline.
• C. They determine how much energy is lost as heat through recombination.
• D. They affect how far gas bubbles block light and reduce active area.

6. Which statement best summarises the trade-off described in Paragraph D?

• A. No single material is best for efficiency, durability and cost at once.
• B. Tandem absorbers are efficient but cannot be protected from corrosion.
• C. Earth-abundant catalysts are cheaper but absorb only ultraviolet light.
• D. Protective coatings improve durability but prevent charge transfer.

7. What point is made in Paragraph E about judging PEC devices?

• A. Efficiency should be calculated using the lower heating value of hydrogen.
• B. Devices should run for 1000 hours before any efficiency is reported.
• C. A long-lasting device with moderate efficiency may give cheaper hydrogen.
• D. Short tests under one sun are the best guide to real-world performance.

8. Most industrial hydrogen today is produced by __________.

9. In many lab prototypes, the electrolyte is an __________ solution.

10. Bubble coverage can block light and reduce the __________.

11. Some studies assume standard sunlight of __________ per square metre.

12. Which material, valued for its chemical stability, did early research in Japan make popular for photoanodes?

13. Which part of the solar spectrum does this material mainly absorb?

14. In some demonstrators, which side of the cell is kept at a slightly higher pressure?

15. On clear, calm summer nights, large U.S. cities are never more than 3°C warmer than their rural surroundings.

16. After sunset, rural areas lose heat more quickly than built-up areas.

17. The Barcelona researchers also recorded air temperatures at street level.

18. Planning rules in Stuttgart allow new buildings to be placed across the valley pathways that carry air into the city.

19. Which paragraph contains information about heat released by vehicles, air conditioners and industry as an additional source of urban warming?

• A
• B
• C
• D
• E
• F
• G

20. Which paragraph contains information about concerns that mobile sensor data and satellite observations may be incomplete or biased?

• A
• B
• C
• D
• E
• F
• G

21. Which paragraph contains information about why the heat island may be weaker in coastal cities?

• A
• B
• C
• D
• E
• F
• G

22. Which paragraph contains information about a link between the age of residents and heat-related emergency calls?

• A
• B
• C
• D
• E
• F
• G

23. Which paragraph contains information about a programme that lowered surface temperatures more than air temperatures?

• A
• B
• C
• D
• E
• F
• G

28. The writer believes that public memory becomes trustworthy when it claims complete neutrality.

29. The writer believes that immersive narrative exhibitions attract more visitors than object-centred galleries.

30. The writer presents procedural standards, such as open archives and independent review, as a pragmatic alternative to memory laws.

35. reported that posts with a single striking image and a short caption spread further than links to long explanations

36. argued that modern states rely more on monuments, anniversaries and museums because everyday traditions no longer pass on the past

37. distinguished informal recollections shared within families from formal representations preserved across generations

38. According to the passage, public memory differs from individual recollection because it is

39. The author suggests that the most reliable form of public memory is the one that is

40. Research on historical misinformation online found that corrective posts from official institutions usually spread widely only when they are